Effect of lithium content on the mechanical and corrosion behaviors of HCP binary Mg–Li alloys

Abstract

The microstructure, crystallographic texture, mechanical properties and corrosion resistance of as-extruded HCP Mg-xLi (x = 1, 3, 5; in wt%) alloys were investigated. The results indicated that the HCP Mg-5Li alloy with high lithium content exhibited a low degree of dynamic recrystallization (DRX) compared with Mg-1Li and Mg-3Li alloys. Besides, the 45° base (0001) texture of Mg-1Li alloy could turn into (11–20) and (10–10) prismatic texture of Mg-3Li and Mg-5Li alloys with c-axis approximately parallel to transverse direction (TD). As a result, the strong prismatic texture resulted in the mechanical anisotropy of as-extruded Mg-3Li and Mg-5Li alloys with higher mechanical strength and low elongation along extrusion direction (ED) (reverse for TD sample). Regarding of corrosion behaviors, filiform corrosion occurred in the three Mg–Li alloys, whilst the high lithium content could mitigate the groove-like corrosion and improve the corrosion resistance of Mg-5Li alloy, which was ascribed to the refined grains, prismatic texture and surface film.